reverse

Conformance: R5RS Scheme

Purpose: Reverse a list.

Arguments:
A - list

Model:

(define (reverse a)
  (cond ((null? a) a)
    (else (append (reverse (cdr a))
                  (list (car a))))))

Implementation:

(define (reverse a)
  (letrec
    ((_reverse
       (lambda (a b)
         (cond ((null? a) b)
           (else (_reverse (cdr a)
                   (cons (car a) b)))))))
    (_reverse a '())))

Example:

(reverse '(a b c d e f)) 
=> (f e d c b a)

See also:
append, length, map, equal?, list?.